My experience has been that sometimes if polyester pants get too hot in the dryer, the wrinkles are impossible to remove. Run and get a new pair. You'll never be happy with wrinkly pants. Good luck in Vegas!

Polyester, being permanent press, is also 'permanent wrinkle' if it runs into the wrong conditions.

Fortunately, there's a simple remedy--you probably have it in your house. Dab the wrinkles lightly with white vinegar, then press. Or, if it's a wide area, I dip a paper towel in white vinegar, wring it out well, and use as a press cloth. The chemicals in vinegar release wrinkles and--as long as you don't wash or dry with heat, should be a permenent solution.

This method can also be used to press permanent pleats and creases into polyester, if you like.

I put wrinkled clothes in the dryer with a dryer sheet or a slightly wet towel. Set it for ten to fifteen minutes. Remove and hang or wear immediately.

Azzalea has it right: using a very warm steam-iron with the vinegar-dampened towel will set creases -or remove wrinkles- in polyester and poly-cotton blend fabrics. I learned about this from a professional seamstress when polyester fabrics were first available, and it still works. You can continue to machine wash and dry the clothes; the vinegar-set crease will remain for numerous washings. Polyester fabrics will remain looking fresh longer if one removes the item from the dryer while it's still slightly damp, let it finish drying on a hanger.